マスダ ヨシキ   Yoshiki Masuda
  益田 芳樹
   所属   川崎医療福祉大学  医療福祉学部 臨床心理学科
   職種   特任教授
論文種別 原著
言語種別 英語
査読の有無 査読なし
表題 Scanning electron microscopic observations on spicules, gemmule coats, and micropyles of the freshwater sponges, Eunapius ryuensis (Sasaki).
掲載誌名 正式名:Kawasaki Medical Journal, Liberal Arts and Science Course
ISSNコード:03865398
巻・号・頁 17,35-44頁
著者・共著者 Masuda Yoshiki, Kuniyasu Satoh
発行年月 1991/12
概要 Eunapius ryuensis was first collected in Korea by Sasaki in 1938. This species was recently collected from a pond in Okayama Prefecture, Japan and is here recorded for only the second time. The useful taxonomic characteristics of the spicules, gemmule coats, and micropyles of this species were studied by scanning electron microscopy and the findings are reported.
Gemmules with a rounded conical outline found freely and singly throughout the skeletal network. The pneumatic layer was well but unevenly developed. At the base of each gemmule, this layer consisted of one to several layers of low polygonal prismatic alveoli. There was a gradual increase in the number of layers of alveoli toward the micropyle. Some of gemmoscleres were attached to the whole surface of the gemmule tangentially, whereas others embedded in a pneumatic coat near an inner gemmular membrane tangentially. The micropyle was tubular and traversed the thick pneumatic layer. Megascleres were of two type; amphioxea and amphystrongyla. Both types were entirely smooth. Microscleres were absent. Gemmoscleres were fusiform with some having sharp ends and others rounded ends. Only a small number recurved spines were noted on the surface.
Our findings corresponded to those of Sasaki with the exception of the diameter of the gemmules, the presence of a pneumatic layer at base of the gemmule and the number of spines on gemmoscleres.
In many respects, E. ryuensis resembles E. coniferus. The major distinction between the two species is the distribution of gemmoscleres, because the gemmoscleres of the latter are embeddded in the pneumatic layer only near the micropyles. The characteristic structure of E. ryuensis resembles that of any species of Eunapius. Therefore, it is an important species when one study the systematic of Eunapius.